Question: $\dfrac{9}{8} - \dfrac{6}{4} = {?}$
Answer: $ = {\dfrac{9 \times 1}{8 \times 1}} - {\dfrac{6 \times 2}{4 \times 2}} $ $ = {\dfrac{9}{8}} - {\dfrac{12}{8}} $ $ = \dfrac{{9} - {12}}{8} $ $ = -\dfrac{3}{8}$